This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. This general user proposal represents a joint effort between the Van Duyne and Bushman laboratories at the University Of Pennsylvania School Of Medicine. We propose the use of the Gl Beamline at CHESS to study the synaptic complex formed between HIV Integrase the integrase binding protein called Lens Epithelial Derived Growth Factor (-EDGF), and substrate DNA in solution, using small-angle x-ray scattering (SAXS). This analysis will complement biophysical and biochemical studies already il progress. Using available high resolution crystal structures of the various components, this scattering data will allow us to construct a low resolution model for synapsis, interaction with binding protein, and catalysis with[unreadable]n the nucleoprotein complex. Currently, there is no experimental structure of an IN/DNA complex available.